The present invention relates to an arrangement and a method for height adjustment of the upper attachment point of a safety belt, arranged in a vehicle with a vehicle seat which is spring-mounted in the vertical direction.
Height-adjusting arrangements for the upper attachment point of safety belts in vehicles are previously known. From U.S. Pat. No. 5,102,166, for example, a height-adjusting arrangement for the upper attachment point of a safety belt is previously known, where the movement of the attachment point is a function of the movement in the longitudinal direction of the vehicle of a seat arranged in the vehicle. The movement of the seat is transmitted via a wire to a slide which runs in a vertical guide groove which is arranged in the body of the vehicle and is positioned at shoulder height of a person sitting in said seat. Said guide groove comprises an upper and a lower end-position stop, which stops prevent the upper attachment point of the safety belt ending up too high or, respectively, low when the seat is located in its rear or, respectively, front position. The arrangement described above therefore means that when, for example, a tall person moves the seat backwards so as to achieve a suitable driving position, the upper attachment point is displaced upwards and in this manner takes up a position in the vertical direction which is optimum for said person.
However, this previously known height-adjusting arrangement has the disadvantage that the movement of the upper attachment point of the safety belt takes place only as a function of the movement of the seat in the longitudinal direction of the vehicle. As it is common, in particular in lorries, buses and various types of utility vehicle, to provide vehicle seats with spring-mounting in the vertical direction in order to improve the comfort of occupants of the vehicles, the height of the vehicle seat should also be taken into consideration for satisfactory adjustment of the upper attachment point of the safety belt.
From EP 447,364, it is previously known, in a vehicle with a vehicle seat which is spring-mounted in the vertical direction, to arrange the upper attachment point of the safety belt on the backrest of the vehicle seat, which results in the attachment point being correctly positioned irrespective of the springing movement of the vehicle seat.
Although the known arrangement provides good adaptation of the upper attachment point of the safety belt during the springing movement of said vehicle seat, it suffers from certain disadvantages. One disadvantage is that the construction of the vehicle seat is relatively complicated as it has to be provided with strong reinforcements. Another disadvantage is that the vehicle seat usually has to be provided with means, for example a wire extending between the vehicle seat and the floor of the vehicle, in order to limit the springing movement in the event of, for example, heavy braking of the vehicle. Furthermore, the abovementioned arrangement means that the floor of the vehicle has to be reinforced, which increases the weight of the vehicle.
The principal object of the present invention is therefore to provide an arrangement and a method for height adjustment of the upper attachment point of a safety belt, arranged in a vehicle with a vehicle seat which is spring-mounted in the vertical direction, where the upper attachment point is arranged so as to follow in the vertical direction the springing movement of said vehicle seal. This is achieved by means of an arrangement and a method of the type referred to in the introduction, the characteristic features of which emerge from independent claims 1 and 11.
Further advantages and objects of the invention can be understood with the aid of the claims below and the description below.